Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
trung va » truong va, trang va, trung ha
thanh va » thanh van, hanh va, thanh ha
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat
cuu tre » cua tre, cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang xa hoi. hieu van cau ((truc va) OR (trung va)) thanh va ((cuu tre) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang xa hoi. hieu van cau ((truc va) OR (trung va)) thanh va ((cuu tre) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang xa hoi. hieu van cau ((truc va) OR (trung va)) thanh va ((cuu tre) or (cua vat))".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang xa hoi. hieu van cau ((truc va) OR (trung va)) thanh va ((cuu tre) or (cua vat))*.